by
Charles, Randall I.

Answer

63, 127

Work Step by Step

For each term n, add $2^n$ to get the next term.
$\underset{+2^1}{\underset\Rightarrow{1}}, \underset{+2^2}{\underset\Rightarrow{3}},\underset{+2^3}{\underset\Rightarrow{7}}, \underset{+2^4}{\underset\Rightarrow{15}},\underset{+2^5}{\underset\Rightarrow{31}},\underset{+2^6}{\underset\Rightarrow{63}}, 127$, . . .